Miscarriage Causes: HLA Matching

A fundamental part of HLA function is the presence of MHC molecules on all cells in the body. While there must be great similarity between these HLA genes with the donor and recipient during a transplant, this does not hold true when considering an embryo. New literature has shown that there are immune privileged sites in the body that generate tolerance for "grafted" tissue through differences in Key HLA genes. These sites are the eye, testicle and the uterus to name a few. There are reasons an embryo must have significant differences than the mother in order for a pregnancy to be successful and not result in miscarriage. Evolution has resulted in significant variation in the shape and sizes of MHC molecules (It is the MHC molecules that pick up virus and bacteria and present it to the immune system for eradication). The variation of the MCH molecules prevents a virus or bacteria from mutating and then evading the immune system in every person they infect, preventing an entire population form getting wiped out during an outbreak. Nature has a reason therefore to try and reject an embryo in couples with similar HLA genes as this would eliminate the ability to diversify.

Other HLA molecules on the Paternal sperm surface, however, play an important role in beginning the process of immune tolerance. One theory is that a difference between the HLA genes of the mother and the paternal sperm and later the embryo tissue itself starts a mechanism for the generation of tolerance in the mothers immune system .From here, there are a series of events in the maternal immune system that turn off its attacking aspects and actually develop cells to protect the embryo called T regulator cells.

Success After Multiple Miscarriages

Differences of HLA genes between the mother and the embryo depend on those of the father, as it is a combination of each parents' genes which determine those of the embryo. Dr. Braverman therefore checks the HLA status of both parents to determine whether or not HLA matching is the issue or other factors are responsible for the defective function of cells and resultant recurrent miscarriages. Due to the way the immune system works, attacks on the embryo due to HLA similarity may occur during early pregnancy, later in pregnancies or even in future pregnancies. Our team will take a comprehensive approach to increasing your ability to complete pregnancies successfully.

Read our blog on HLA analysis.

Contact a reproductive specialist from Braverman IVF & Reproductive Immunology for an examination of your HLA status and how this may be affecting your pregnancies.

View our informational video about this topic by clicking on the video screen below or by clicking here.